The invention concerns a compact filter, in particular a compact air filter for motor vehicles, comprising a compact filter element for exchangeable use in a filter housing, wherein the compact filter element comprises a filter body of web-shaped filter medium in which at least one flat filter medium web and one corrugated filter medium web are placed on each other and are at least partially connected to each other across partial areas by means of ultrasonic welding.
The invention concerns moreover a method for producing a compact filter, in particular a compact air filter for motor vehicles, comprising a compact filter element for exchangeable use in a filter housing in which a filter body of the compact filter element is made from web-shaped filter medium, wherein at least one flat filter medium web and one corrugated filter medium web are placed on each other and are at least partially connected to each other across partial areas by means of ultrasonic welding.
The invention concerns moreover a filter medium, in particular a web-shaped filter medium, in particular a filter body of a compact filter element, preferably for exchangeable use in a filter housing of a compact filter, in particular a compact air filter for motor vehicles, in which at least one flat filter medium web and one corrugated filter medium web are placed on each other and are at least partially connected to each other across partial areas by means of ultrasonic welding.
When filtering air, so-called compact filters are widely used that are in particular formed of layered filter paper. A corrugated filter paper web is attached to a flat filter paper web. The thus formed semi-finished product is wound to a filter body or stacked, as a result of which a plurality of parallel extending gas passages are created. These gas passages are closed alternatingly by plugs. Incoming air flows from the raw side (unfiltered side) into the gas passages open at the inlet side and is forced by the plugs at the outlet side to pass through the filter walls into the neighboring gas passages. From here, the filtered air flows through the gas passages that are open at the outlet side to the clean side (filtered side) of the filter.
WO 2007/035802 A1 discloses a filter and a method for producing such a filter. The filter is made by winding a web-shaped filter medium to a coil. The filter medium is formed of a flat filter medium web and a corrugated filter medium web that are attached to each other by means of ultrasonic welding. The filter webs are made of polyester nonwoven.
The invention has the object to design a compact filter, a filter element, and a method of the aforementioned kind in such a way that a filter with optimal filtering action and an optimal service life can be realized in a simple and reliable way.